Model and actress Kim Porter was found dead yesterday in her California home at age 47. While the cause of death is still undetermined, People reported that she may have been suffering from pneumonia in the weeks leading up to her death.

Although pneumonia is certainly unpleasant and can be dangerous in some cases, it usually improves with treatment within a few weeks. So how does a person–especially a young one, if Porter was indeed killed by the disease–die from pneumonia? Health spoke to Tanaya Bhowmick, MD, assistant professor of medicine in infectious diseases at Robert Wood Johnson Medical School in New Jersey to find out.

What is pneumonia?

First, a refresher: Pneumonia is a lung infection caused by bacteria, viruses, or fungi. Like colds or flu, it’s often spread this time of year through coughing, sneezing, or touching germy surfaces (and then touching your face). Speaking of the flu, pneumonia can even be a complication of a bad bout with the influenza virus; the flu is a common cause of pneumonia in adults, according to the American Lung Association (ALA).

When the guilty virus, bacterium, or fungus enters your lungs, air sacs called alveoli can fill with fluid. That inflammation produces the classic symptoms of pneumonia, such as cough, fever, and difficulty breathing.

What are the chances of dying from pneumonia?

Yes, pneumonia can kill–but it’s rare. “We see so many more people that have pneumonia that survive,” Dr. Bhowmick says.

According to the Centers for Disease Control and Prevention (CDC), every year there are around 1 million Americans sent to the hospital with pneumonia, and about 50,000 die from the disease.

How does someone die from pneumonia?

Pneumonia has to be quite severe for it to kill someone, Dr. Bhowmick stresses. The lungs, of course, are responsible for supplying oxygen all over the body. Pneumonia, it follows, threatens your oxygen tank. “If it’s so severe that it’s essentially cutting off oxygen supply, then the rest of your vital organs aren’t getting enough oxygen,” she explains.

At the same time, a person’s body is also launching an inflammatory response in an attempt to fight off the infection, Dr. Bhowmick says. But that can result in changes in blood pressure that might in turn decrease blood supply to those organs, too. That’s a dangerous combination, she explains, because not only is blood supply reduced, but that blood has less oxygen in it. “That leads to abnormalities of heart function, kidney function–the organs stop working,” Dr. Bhowmick says, “and that leads to death.”

Who is most at risk?

Like with many other conditions, a person’s ability to fight off pneumonia is greater the healthier they are to begin with. Pneumonia is more likely to be serious or even deadly in infants, adults over 65, and people with underlying health issues or weakened immune systems, like someone with cancer or HIV, Dr. Bhowmick says–although it's possible a severe case of pneumonia could turn deadly in someone at any age.

With treatment–which varies depending on the type of pneumonia a person has–most people improve within one to three weeks. That’s more likely if you’re younger than 65, generally healthy, and your pneumonia is caught early enough that it hasn’t spread, according to the ALA.

How can someone with pneumonia stay safe?

“Seeking out care from your doctor is the most important thing,” Dr. Bhowmick says. He or she can help determine what type of pneumonia you have and therefore what kind of treatment you might require. (For example, antibiotics are only helpful against bacterial pneumonia, while some people with a viral infection might benefit from antiviral medications.)

No matter what type of pneumonia you have, you’re going to want to stay hydrated and get plenty of rest, Dr. Bhowmick adds. That rest is crucial, according to the ALA, because rushing back to work or the gym before you’re fully recovered could lead to a relapse of the infection.

Of course, it’s better still if you never get pneumonia to begin with. A smart first step? Getting your flu vaccine, since the virus can lead to pneumonia infection. Talk to your doctor if you’re older than 65 or living with a chronic health condition; you could be a good candidate for one of two pneumonia vaccines that protect against specific bacteria.

It also never hurts this time of year to make sure you’re religiously washing your hands, Dr. Bhowmick adds, and doing your best to avoid people who are sneezing or coughing.